A hot water heater that heats a vehicle interior using heat of engine coolant is frequently used as a conventional vehicle heating device. A heat pump air-cooling device that cools air sent to the vehicle interior using a low-temperature refrigerant of a heat pump is typically used as a conventional vehicle air-cooling device.
PTL 1 discloses a vehicle air conditioner that is based on the hot water heater and the heat pump air-cooling device, which are used in the conventional vehicle, and has improved heating performance by adding an auxiliary heating function of further heating the engine coolant by the heat pump using a compressor and a refrigerant. They are common to an air-cooling period and a heating period.
In addition to a heat generating component, such as an engine, which usually needs cooling using coolant, a component of which temperature is to be controlled, which is, for example, an onboard device such as an oil cooler and an inverter, which needs cooling and warming, is known in various component mounted on the vehicle.